我正在使用 Jiql 连接到 GAE 上的数据存储，但是当我尝试打开数据库连接并执行查询时，出现以下错误。
问题是，是因为缺少 EntityNotFoundException 类还是因为缺少数据存储中的实体之一？由于我对此完全陌生，有人可以解释错误输出吗？
Starting Jetty on port 8888
[WARN] Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract void com.baytex.zoopreel.client.services.StartupService.startSession()' threw an unexpected exception: java.lang.NoClassDefFoundError: com/google/appengine/api/datastore/EntityNotFoundException
at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:385)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:588)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:208)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1097)
at com.baytex.zoopreel.server.EncodingFilter.doFilter(EncodingFilter.java:28)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1088)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)
Caused by: java.lang.NoClassDefFoundError: com/google/appengine/api/datastore/EntityNotFoundException
at org.jiql.jdbc.jiqlConnection.<init>(jiqlConnection.java:59)
at org.jiql.jdbc.Driver.connect(Driver.java:89)
at com.baytex.server.db.connector.PMF.get(PMF.java:31)
at com.baytex.zoopreel.server.StartupServiceImpl.startSession(StartupServiceImpl.java:211)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)
... 25 more
Caused by: java.lang.ClassNotFoundException: com.google.appengine.api.datastore.EntityNotFoundException
at java.lang.ClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:352)
at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:337)
... 34 more
[ERROR] 500 - POST /zoopreelgwt/startup (localhost) 57 bytes